{"id":"6bc2fb2f-2f4e-5a9d-9aa1-c5154c8e37db","stable_key":"35ec55a7-323c-5c28-979e-3bdafe9d5769:ph-equilibria","predicate":"context_dependent_observation","statement":"Solution pH changes reversible molecular-form transitions of the tested anthocyanin glucosides; degradation is a separate process.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"8b622b6a-e74b-5867-959c-3d77e2a98829","mechanism_event_label":"Solution pH changes reversible molecular-form transitions of the tested anthocyanin glucosides; degradation is a separate process.","subject":{"id":"75149db0-02f7-5d32-8c7a-5c111d90d8ee","slug":"cyanidin-3-glucoside","display_name":"Cyanidin 3-O-beta-D-glucopyranoside","entity_type_key":"small_molecule"},"object":{"id":"62463fa3-cc60-5038-9dbd-ba91e8fedc80","slug":"anthocyanin-ph-dependent-form-equilibrium","display_name":"Anthocyanin pH-dependent reversible molecular-form transitions","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"8b622b6a-e74b-5867-959c-3d77e2a98829","stable_key":"35ec55a7-323c-5c28-979e-3bdafe9d5769:ph-equilibria-event","event_type":"biochemical_relationship","label":"Solution pH changes reversible molecular-form transitions of the tested anthocyanin glucosides; degradation is a separate process.","description":"**pH changes molecular form.** Experiments with four purified 3-O-glucosides distinguish reversible proton transfer, hydration and cis/trans isomerization from irreversible degradation. Flavylium, quinoidal, hemiketal and chalcone states are a reaction network whose populations and rates depend on the particular compound and solution. Color loss alone cannot identify the reaction. Neither one universal form at blood pH nor one universal plasma half-life follows from these solution experiments. [Sousa and colleagues, 2022](https://pubmed.ncbi.nlm.nih.gov/34982560/).","status":"provisional","compartment":null,"participants":[{"entity":{"id":"75149db0-02f7-5d32-8c7a-5c111d90d8ee","slug":"cyanidin-3-glucoside","display_name":"Cyanidin 3-O-beta-D-glucopyranoside","entity_type_key":"small_molecule"},"role":"tested factor","stoichiometry":null,"state_label":"as reported","sequence_order":0,"notes":""},{"entity":{"id":"62463fa3-cc60-5038-9dbd-ba91e8fedc80","slug":"anthocyanin-ph-dependent-form-equilibrium","display_name":"Anthocyanin pH-dependent reversible molecular-form transitions","entity_type_key":"cellular_process"},"role":"measured outcome","stoichiometry":null,"state_label":"mixed","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary indexed abstract reviewed; full methods, figures, exact doses or endpoint-specific species assignments may remain unextracted.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified anthocyanin aqueous-solution kinetics; exact compound and pH dependence.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"interpretation_status","value_text":"Source-derived extraction of a fact-checked reference; access is explicit, not independent raw-data verification.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Interpret only within the recorded preparation, exposure and comparator. The complete source passage retains qualifications; unspecified doses/timing have not been extracted here. No clinical efficacy, nutrient deficiency or unique molecular mediation is inferred.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Solution pH changes reversible molecular-form transitions of the tested anthocyanin glucosides; degradation is a separate process.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"A New Insight into the Degradation of Anthocyanins: Reversible versus the Irreversible Chemical Processes. | 2022 | DOI 10.1021/acs.jafc.1c06521 | PMID 34982560 | https://pubmed.ncbi.nlm.nih.gov/34982560/ | https://doi.org/10.1021/acs.jafc.1c06521","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"source_locator","value_text":"Reviewed reference lines 11-11; exact primary location described in quoted passage where extracted.","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"9de149bb-25f6-5d65-9c7b-f2677a818619","evidence_kind":"source_excerpt","locator":"Lines 11-11","start_line":11,"end_line":11,"excerpt":"**pH changes molecular form.** Experiments with four purified 3-O-glucosides distinguish reversible proton transfer, hydration and cis/trans isomerization from irreversible degradation. Flavylium, quinoidal, hemiketal and chalcone states are a reaction network whose populations and rates depend on the particular compound and solution. Color loss alone cannot identify the reaction. Neither one universal form at blood pH nor one universal plasma half-life follows from these solution experiments. [Sousa and colleagues, 2022](https://pubmed.ncbi.nlm.nih.gov/34982560/).","model_system":"Purified anthocyanin aqueous-solution kinetics; exact compound and pH dependence.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Exact excerpt of the retained AI-assisted reviewed reference; primary sources are cited in primary_references and access scope is retained. Not a verbatim quotation from a primary paper.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"b08e7f7d-4d34-56d7-a185-2124f8d72b3c","stable_key":"import-35ec55a7-323c-5c28-979e-3bdafe9d5769","title":"Anthocyanins: detailed mechanisms of action (reviewed 4 October 2026)","document_type":"imported_text","citation_label":"Original AI-assisted review of primary studies and, where relevant, official regulatory records. Access level is retained per claim. Corrections, null results and unresolved questions remain explicit. Not publisher full text or independent replication.","file_path":"","sha256":"7cff1a47fbd9c625412b84162b1c823004b4162b7c009f9a11d5807fb8e04ef9","revision_id":"1bd4fa42-bfeb-5148-8250-fc363d8c1de0","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}